Bottom ring-wiper strip assembly and method of making it



ly 2 1967 w. w. URMETZ ETAL 3,332,659

BOTTOM RING-WIPER STRIP ASSEMBLY AND METHOD OF MAKING IT Filed Aug. 13, 1962 INVENTOR.

WALTER w. URMETZ BY JOEL c. CARPENTER ATT RNEYS United States Patent 3,332,659 BOTTOM RING-WIPER STRIP ASSEMBLY AND METHOD OF MAKING IT Walter W. Urmetz, Seven Hills, and Joel C. Carpenter,

Chagrin Falls, Ohio, assignors to Oglebay Norton Company, Cleveland, Ohio, a corporation of Delaware Filed Aug. 13, 1962, Ser. No. 216,453 Claims. (Cl. 249202) This invention relates to a bottom ring-wiper strip assembly for a hot top adapted to be used with an ingot mold in the pouring of molten metal, such as steel, to produce an ingot.

This application is directed toward subject matter disclosed in our copending application Ser. No. 62,757, now US. Patent No. 3,058,182, filed Oct. 14, 1960, as a continuation-in-part of our earlier application Ser. No. 815,852, now abandoned, filed May 26, 1959, which also disclosed the subject matter of this application.

As is well known in the art, hot tops are placed in the open upper ends of ingot molds and the molten metal is poured through the hot tops into the molds until they are filled and the hot tops contain a volume of the molten metal sufiicient for the hot tops to function to feed the molten metal into the pipes or shrinkage cavities tending to form in the solidifying ingots.

' A common form of reusable floating type hot top comprises a refractory lined metal casing to the lower end of which a single use refractory bottom ring is attached by means of wire attaching clips.

The hot top usually is provided with a sheet metal wiper strip, the function of which is to form a seal between the hot top and the inner wall of the ingot mold to stop ofi the rising molten metal that enters the clearance space between the hot top and said wall. In other words, the function of the wiper strip is to seal off this clearance space to prevent the molten metal from rising too far therein or from overflowing the top edge of the mold. When the molten metal rises too far in this clearance space, it is apt to form a fin around the hot top casing which would cause stickers when the hot top is being stripped from the sinkhead and the mold after the ingot has solidified. If the molten metal overflows the upper end of the mold and solidifies, it can produce hanger ingots causing hanger cracks on the surface thereof and interfering with the floating movement of the hot top relative to the ingot mold.

One object of the present invention is to provide a new and improved bottom ring and wiper strip assembly which can be handled and shipped as a unit and in which the wiper lip is supported on the ring by means integral with the lip and cooperating with the outer peripheral face, i.e., vertical side, of the ring to form a unitary structure therewith for handling and shipping and which comprises a continuous closed band which encircles the outer periphery of the ring.

It has proved desirable that the bottom ring and wiper strip used with the hot top be a unitary assembly so that it may be handled, shipped and applied as a unit. Problems arise in providing a simplified method of attaching a wiper strip to a bottom ring. Heretofore, the methods or constructions which have been used to connect wiper strips to the bottom ring have required special provision in the ring for either locating or attaching, or both, the wiper strip on the ring. This means that a simple bottom ring cannot be used to form the assembly and, therefore, the apparatus for molding the ring becomes more complicated since the ring must be molded with the necessary provisions for either attaching or locating the wiper strip. Obviously, this complicates the molding operation. While wiper strips can beattached to the bottom ring by nailing, embedding, etc., this complicates the molding apparatus which makes it more costly and difficult to produce the ring.

Accordingly, another object of the present invention is to provide a new and improved bottom ring-wiper strip assembly for a hot top wherein the wiper strip is frictionally connected to the bottom ring and does not require special provisions on the ring or wiper strip to effect the interconnection of the strip and ring.

Another object of the present invention is to provide a new and improved bottom ring-wiper strip assembly for a hot top in which the wiper strip is tightly connected to the bottom ring in such a manner that the molding of the ring is not complicated by the fact that the ring must be provided with means for attaching or locating, or both, the wiper strip on the ring.

Yet another object of the present invention is to provide a new and improved bottom ring-wiper strip assembly for a hot top wherein the wiper strip is connected to the bottom ring with a friction fit and is constructed in such a manner so as to be held against vertical displacement relative to the ring when a hot top with the assembly thereon is inserted into an ingot mold.

A further object of the present invention is to provide a new and improved method of attaching a wiper strip to a bottom ring for a hot top, which method enables the use of a bottom ring that has no special provision for attaching the wiper strip thereto but, yet, will provide a tight connection between the ring and wiper strip.

A still further object of the present invention is to provide a new and improved bottom ring-wiper strip assembly wherein the wiper strip is constructed and attached to the bottom ring in such a manner that the ring is strengthened.

In accordance with the present invention, a wiper strip is connected to a bottom ring for a hot top with a friction fit to provide a bottom ring-wiper strip assembly which may be shipped and handled as a unit with the wiper strip having a portion extending along the bottom face of the ring to prevent displacement of the wiper strip upwardly when a hot top with the bottom ring-wiper strip assembly thereon is inserted into an ingot mold.

Further objects and advantages of the present invention will be apparent from the following detailed description thereof made with reference to the accompanying drawing forming a part of the present specification for all matters therein and in which:

FIG. 1 is a vertical cross-sectional view of a hot top in position on an ingot mold, shown fragmentarily, the hot top having a bottom ring-wiper strip assembly thereon in accordance with the present invention;

FIG. 2 is a top plan view of the bottom ring-wiper strip assembly shown in FIG. 1; and

FIG. 3 is an exploded side elevational view of the bottom ring-wiper strip assembly illustrating method of assembly.

The hot top shown in FIG. 1 comprises the usual metal casing 16 which is illustrated as a two-part casing but it could be a one-part casing. The interior of the casing 16 is lined with refractory material which is illustrated in the form of firebrick 17, as will be understood in the art. A refractory bottom ring 18 is secured to the lower end of the hot top so as to underlie the hot top casing 16 and the brick lining 17, as will be understood in the art.

The hot top in use is positioned in the upper end of an ingot mold 19 and molten metal is poured into the mold to fill the same and provide a quantity thereof in the hot top to form a sinkhead for a purpose well known in the art. The bottom ring 18 has an upper planar surface portion 18a which underlies the lower end of the casing 16 and an inner upstanding continuous ring portion 1812 which extends upwardly within the lower end of the casing 16 and underlies the lower end of the refractorylining 17 as is Well understood in the art. The bottom ring is secured to the hot top by means of a number of attaching clips 20, one form of which is shown in the drawing.

The casing 16 and bottom ring 18 are so dimensioned as to be positioned in the mold 19 with clearance space existing between the outer side of the casing 16 and bottom ring 18 and the inside Wall of the mold. The width of this clearance space will vary, due to tolerances required in the manufacture of the mold.

When molten metal is poured into the ingot mold, the molten metal rises into the clearance space between the hot top and interior wall of the mold and it has been customary to provide a seal in the form of wiper strips which have integral wiper lips that extend angularly outwardly and upwardly from the periphery of the bottom ring and contact the wall of the mold when the hot top is inserted therein. The wiper lips function to limit the upward flow of the molten metal in the clearance space between the hot top and the mold wall.

The wiper lip of the wiper strip is dimensioned so it will tightly. contact the inner wall of the mold when the hot top is inserted in the mold and it can be flexed inwardly by such contact depending upon the width of the clearance space between the hot top and mold.

The wiper lip of the wiper strip in addition to providing a mechanical seal due to its contact with the mold Wall also has a chilling effect on the molten metal in the clearance space that contacts the wiper lip and this facilitates the required solidification of such molten metal.

The wiper strip means may be made as an integral stamping or it may be made of several stampings secured together to form the complete unit as, for instance, by welding, riveting, or otherwise suitably securing the several stampings together. The wiper strip means is of sheet metal.

The wiper strip means of the embodiment shown has an attaching and bottom ring engaging portion formed of a flange part 22 which extends beneath and contacts the lower face 18d of the bottom ring 18. The flange part 22 is integral with and extends from the lower end of a vertically extending part 23 which, when applied to the bottom ring, tightly contacts the outer periphery or face 18a of the flange of the bottom ring as clearly indicated in FIG. 1.

The vertical part 23 fits the lower outer periphery of the ring with a tight fit and at the upper end of the vertical part 23 of the attaching and bottom ring engaging portion of the'wiper strip means there is an integral outwardly and upwardly inclined or flared wiper lip 24. The Wiper strip means is applied to or telescoped on the bottom ring as a unit and is held in position on the bottom ring by its fit thereon.

When the'hot top is inserted into the ingot mold, the ring shown in the illustrated embodiment will be held against displacement upwardly with respect to the ring by the engagement of the flange 22 with the bottom face of the ring. The bottom flange 22 will prevent upward displacement of the wiper strip even though the forces applied during insertion into the ingot mold are sufficiently large to overcome the frictional engagement between the outer periphery of the ring and the wiper strip.

It will be noted that when the bottom ring assembly of the present invention is secured to the lower end of the hot top, the attaching clips 20 extend beneath the flange part 22 of the attaching portion of the wiper strip and upwardly alongside and outwardly of the vertical part 23 thereof and through cutouts or slots 27 formed in the wiper lip 24.

Also the vertical part 23 and the flange part 22 of the wiper strip means at their angle of interconnection are preferably provided directly below the slots 27 with the slots 28 for receiving the clips 20, the vertical portion of each of the slots 28 preferably extending a substantial distance upwardly of the vertical part 23 from the lower end thereof.

In order to increase the flexibility of the wiper lip, particularly at the corners thereof, said lip may be provided with slits 29, four of which are indicated in FIG. 2, but it will be understood that the number of slits 29 may be increased as is found desirable. Inasmuch as the wiper strip means is a unit which encompasses the periphery of the ring, its correct positioning on the bottom ring is assured and it provides protection for the bottom ring including the lower edge and corners thereof.

The bottom ring and wiper strip assembly is shown separated in FIG. 3 of the drawing. While diiferent methods might be employed to cause the wiper strip to tightly embrace the ring so as to be held thereon by friction, in the preferred method of assembling the wiper strip and ring, the wiper strip is heated before or upon application to the ring to expand the closed vertical part 23 to enable the wiper strip to readily encompass the outer periphery of the bottom ring. In this method the wiper strip then cools and shrinks into tight frictional engagement with the ring. When the Wiper strip is shrunk onto the ring, its natural preshrunk condition is preferably such that the closed portion of the wiper strip is slightly smaller than the outer periphery of the ring. By providing a tight frictional engagement, such as a shrink fit, mechanical interfitting means is not required between the ring and the wiper strip. It will also be noted that the method of assembling the wiper strip to the ring which causes the closed portion ofthe wiper strip to tightly embrace the ring, does not require any specific locating portions on the wiper strip and ring since the wiper strip will essentially only fit in one location on the ring and no additional mechanical means are required to maintain the ring and wiper strip connected.

When the wiper strips are assembled onto the bottom rings by the manufacturer prior to shipment and prior to use by the ultimate user, the wiper strip meansserves to protect the lower edges of the bottom rings against chipping, cracking or other damage during shipment, storage and handling. It will also be noted that the wiper strip means, due to tightly embracing the bottom rings, strengthen the latter in addition to protecting the same and funcion to retain any cracked portions of the rings in proper position with respect to the rings;

It can now be seen that a novel and improved bottom wiper strip assembly has been provided in which the vertical part 23 of the wiper strip means when shrunk onto the bottom ring will inherently put the vertical part. 23 in tension and the tight embracing of the bottom ring will strengthen the latter, as mentioned above, and place the bottom ring in compression to pre-stress the latter. Moreover, it is apparent that the assembly essentially comprises a ring portion 18b having an outer peripheral portion formed by a flange portion 18c extending outwardly from the ring portion 18b. The flange 18c is, as is shown in the drawings, a continuous flanged portion whichextends around the external periphery of the ring portion and has a peripherally constant external contour. Moreover, it is also apparent that the flange 22 and/ or the vertical part 23 of the wiper strip means constitutes securing means for securing the wiper strip means to the bottom ring 18, and that the clip 20 constitutes further securing means which engages the flange 20 and the vertical part 23 as is shown in the drawing for connecting the bottom ring and wiper strip assembly to the hot top.

From the foregoing, it can be seen that the prment invention has provided a new and simplified ring-wiper construction and method of manufacture of the same and further constructions and modifications and arrangements may be made within the ability of those skilled in the art and it is hereby our intention to cover all such constructions, modifications, and arrangements which fall within the ability of those skilled in the art and within the scope and spirit of the present invention.

Having described our invention, we claim:

1. The method of manufacturing a bottom ring-wiper strip assembly for a hot top comprising forming a sheet metal wiper strip having a closed portion adapted to encompass the periphery of the ring with a tight fit and a wiper lip integral with said closed portion, heating the metal forming the closed portion to expand said portion to a size larger than the outer periphery of the ring and shrinking the strip around the outer periphery of the ring into tight frictional engagement therewith.

2. A unitary structure comprising a refractory bottom ring for protecting the underside of a hot top, said bottom ring having inner and outer peripheral faces and a top face to be positioned adjacent the underside of the hot top to be protected and a bottom face, sheet metal wiper strip means mounted on said ring to form a unitary structure therewith and exposing the inner peripheral face of said ring, said wiper strip means comprising wiper lip means extending around said refractory ring and upwardly and outwardly from the outer peripheral face of the refractory ring and means integral with the wiper lip means cooperating with the outer peripheral face of the refractory ring for supporting the wiper lip means on the bottom ring to form a unitary structure therewith cornprising a closed continuous portion extending downward ly from said wiper lip means along the outer peripheral face of the reffractory ring and terminating clear of engagement with the inner peripheral face to expose the latter.

3. A unitary structure as defined in claim 2 wherein said wiper lip means is supported on said bottom ring by tight frictional engagement between the outer peripheral face of the ring and said closed portion.

4. A unitary structure as defined in claim 2 wherein said closed portion has a shrunk fit with the outer periphery of said ring to provide a tight frictional engagement therewith.

5. A unitary structure as defined in claim 2 wherein said closed portion is mounted in tension on said ring to prestress the latter.

6. A unitary structure comprising a refractory bottom ring for protecting the underside of a hot top, said bottom ring having inner and outer peripheral faces and a top f ace to be positioned adjacent the underside of the hot top to be protected and a bottom face, sheet metal wiper strip means mounted on said ring to form a unitary structure therewith and exposing the inner peripheral face of said ring, said wiper strip means comprising wiper lip means extending around said refractory ring and upwardly and outwardly frrom the outer peripheral face of the refractory ring and means integral with the wiper lip means cooperating with the outer peripheral face of the refractory ring for supporting the wiper lip means on the bottom ring to form a unitary structure therewith comprising a closed continuous portion extending downwardly from said wiper lip means along the outer peripheral face of the refractory ring and terminating clear of engagement with the inner peripheral face to expose the latter, said wiper strip means comprising a bottom flange integral with said closed portion and lying along the bottom face of said refractory ring, said flange extending inwardly from the outer peripheral face of the bottom ring and terminating short of the inner peripheral face of the bottom ring.

7. A unitary structure as defined in claim 6 wherein said wiper lip means is supported on said bottom ring by tight frictional engagement between the outer peripheral face of the ring and said closed portion.

8. A unitary structure as defined in claim 6 wherein said closed portion has a shrunk fit with the outer periphery of said ring to provide a tight frictional engagement therewith.

9. A unitary structure as defined in claim 6 wherein said closed portion is mounted in tension on said ring to prestress the latter.

10. A prestressed hot top bottom ring comprising the combination of a refractory ring having an open center, a base face,

and an externally peripherally extending edge face; the base and edge faces being disposed at an angle to each other; and

a continuous wiper ring, mounted in tension upon and surrounding said refractory ring;

said wiper ring exposing the inner peripheral face of said refractory ring and having a base leg and an edge leg disposed at an angle to each other and respectively mounted relative to said refractory ring flush with said base and edge faces;

said wiper ring further including a wiper blade extending from the edge leg outwardly of the hot top bottom ring;

whereby the bottom ring is prestressed by the refractory ring being in compression responsive to the tension of the wiper ring.

References Cited UNITED STATES PATENTS 116,408 6/1871 Britten 22-203 153,630 7/1874 Sweeney 22203 1,755,669 4/1930 Schwab 22--147 1,997,677 4/1935 Charman 22-l47 3,098,270 7/1963 Bauer 22204 1. SPENCER OVERHOLSER, Primary Examiner.

V. K, RISING, Assistant Examiner. 

1. THE METHOD OF MANUFACTURING A BOTTOM RING-WIPER STRIP ASSEMBLY FOR A HOT TOP COMPRISING FORMING A SHEET METAL WIPER STRIP HAVING A CLOSED PORTION ADAPTED TO ENCOMPASS THE PERIPHERY OF THE RING WITH A TIGHT FIT AND A WIPER LIP INTEGRAL WITH SAID CLOSED PORTION, HEATING THE METAL FORMING THE CLOSED PORTION TO EXPAND SAID PORTION TO A SIZE LARGER THAN THE OUTER PERIPHERY OF THE RING AND SHRINKING THE STRIP AROUND THE OUTER PERIPHERY OF THE RING INTO TIGHT FRICTIONAL ENGAGEMENT THEREWITH.
 2. A UNITARY STRUCTURE COMPRISING A REFRACTORY BOTTOM RING FOR PROTECTING THE UNDERSIDE OF A HOT TOP, SAID BOTTOM RING HAVING INNER AND OUTER PERIPHERAL FACES AND A TOP FACE TO BE POSITIONED ADJACENT THE UNDERSIDE OF THE HOT TOP TO BE PROTECTED AND A BOTTOM FACE, SHEET METAL WIPER STRIP MEANS MOUNTED ON SAID RING TO FORM A UNITARY STRUCTURE THEREWITH AND EXPOSING THE INNER PERIPHERAL FACE OF SAID RING, SAID WIPER STRIP MEANS COMPRISING WIPER LIP MEANS EXTENDING AROUND SAID REFRACTORY RING AND UPWARDLY AND OUTWARDLY FROM THE OUTER PERIPHERAL FACE OF THE REFRACTORY RING AND MEANS INTEGRAL WITH THE WIPER LIP MEANS COOPERATING WITH THE OUTER PERIPHERAL FACE OF THE REFRACTORY RING FOR SUPPORTING THE WIPER LIP MEANS ON THE BOTTOM RING TO FORM A UNITARY STRUCTURE THEREWITH COMPRISING A CLOSED CONTINUOUS PORTION EXTENDING DOWNWARDLY FROM SAID WIPER LIP MEANS ALONG THE OUTER PERIPHERAL FACE OF THE REFRACTORY RING AND TERMINATING CLEAR OF ENGAGEMENT WITH THE INNER PERIPHERAL FACE TO EXPOSE THE LATTER. 